2 * OF helpers for the GPIO API
4 * Copyright (c) 2007-2008 MontaVista Software, Inc.
6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/errno.h>
17 #include <linux/module.h>
19 #include <linux/gpio/consumer.h>
21 #include <linux/of_address.h>
22 #include <linux/of_gpio.h>
23 #include <linux/pinctrl/pinctrl.h>
24 #include <linux/slab.h>
25 #include <linux/gpio/machine.h>
29 /* Private data structure for of_gpiochip_find_and_xlate */
31 enum of_gpio_flags *flags;
32 struct of_phandle_args gpiospec;
34 struct gpio_desc *out_gpio;
37 /* Private function for resolving node pointer to gpio_chip */
38 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
40 struct gg_data *gg_data = data;
43 if ((gc->of_node != gg_data->gpiospec.np) ||
44 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
48 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
50 /* We've found a gpio chip, but the translation failed.
51 * Store translation error in out_gpio.
52 * Return false to keep looking, as more than one gpio chip
53 * could be registered per of-node.
55 gg_data->out_gpio = ERR_PTR(ret);
59 gg_data->out_gpio = gpiochip_get_desc(gc, ret);
64 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
65 * @np: device node to get GPIO from
66 * @propname: property name containing gpio specifier(s)
67 * @index: index of the GPIO
68 * @flags: a flags pointer to fill in
70 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
71 * value on the error condition. If @flags is not NULL the function also fills
72 * in flags for the GPIO.
74 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
75 const char *propname, int index, enum of_gpio_flags *flags)
77 /* Return -EPROBE_DEFER to support probe() functions to be called
78 * later when the GPIO actually becomes available
80 struct gg_data gg_data = {
82 .out_gpio = ERR_PTR(-EPROBE_DEFER)
86 /* .of_xlate might decide to not fill in the flags, so clear it. */
90 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
93 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
94 __func__, propname, np->full_name, index);
98 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
100 of_node_put(gg_data.gpiospec.np);
101 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
102 __func__, propname, np->full_name, index,
103 PTR_ERR_OR_ZERO(gg_data.out_gpio));
104 return gg_data.out_gpio;
107 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
108 int index, enum of_gpio_flags *flags)
110 struct gpio_desc *desc;
112 desc = of_get_named_gpiod_flags(np, list_name, index, flags);
115 return PTR_ERR(desc);
117 return desc_to_gpio(desc);
119 EXPORT_SYMBOL(of_get_named_gpio_flags);
122 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
123 * @np: device node to get GPIO from
124 * @chip: GPIO chip whose hog is parsed
125 * @name: GPIO line name
126 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
127 * of_parse_own_gpio()
128 * @dflags: gpiod_flags - optional GPIO initialization flags
130 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
131 * value on the error condition.
133 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
134 struct gpio_chip *chip,
136 enum gpio_lookup_flags *lflags,
137 enum gpiod_flags *dflags)
139 struct device_node *chip_np;
140 enum of_gpio_flags xlate_flags;
141 struct of_phandle_args gpiospec;
142 struct gpio_desc *desc;
146 chip_np = chip->of_node;
148 return ERR_PTR(-EINVAL);
154 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
158 if (tmp != chip->of_gpio_n_cells)
159 return ERR_PTR(-EINVAL);
161 gpiospec.np = chip_np;
162 gpiospec.args_count = tmp;
164 ret = of_property_read_u32_array(np, "gpios", gpiospec.args, tmp);
168 ret = chip->of_xlate(chip, &gpiospec, &xlate_flags);
172 desc = gpiochip_get_desc(chip, ret);
176 if (xlate_flags & OF_GPIO_ACTIVE_LOW)
177 *lflags |= GPIO_ACTIVE_LOW;
179 if (of_property_read_bool(np, "input"))
181 else if (of_property_read_bool(np, "output-low"))
182 *dflags |= GPIOD_OUT_LOW;
183 else if (of_property_read_bool(np, "output-high"))
184 *dflags |= GPIOD_OUT_HIGH;
186 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
187 desc_to_gpio(desc), np->name);
188 return ERR_PTR(-EINVAL);
191 if (name && of_property_read_string(np, "line-name", name))
198 * of_gpiochip_set_names() - set up the names of the lines
199 * @chip: GPIO chip whose lines should be named, if possible
201 static void of_gpiochip_set_names(struct gpio_chip *gc)
203 struct gpio_device *gdev = gc->gpiodev;
204 struct device_node *np = gc->of_node;
208 nstrings = of_property_count_strings(np, "gpio-line-names");
210 /* Lines names not present */
213 /* This is normally not what you want */
214 if (gdev->ngpio != nstrings)
215 dev_info(&gdev->dev, "gpio-line-names specifies %d line "
216 "names but there are %d lines on the chip\n",
217 nstrings, gdev->ngpio);
220 * Make sure to not index beyond the end of the number of descriptors
221 * of the GPIO device.
223 for (i = 0; i < gdev->ngpio; i++) {
227 ret = of_property_read_string_index(np,
234 "unable to name line %d: %d\n",
238 gdev->descs[i].name = name;
243 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
244 * @chip: gpio chip to act on
246 * This is only used by of_gpiochip_add to request/set GPIO initial
248 * It retures error if it fails otherwise 0 on success.
250 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
252 struct gpio_desc *desc = NULL;
253 struct device_node *np;
255 enum gpio_lookup_flags lflags;
256 enum gpiod_flags dflags;
259 for_each_available_child_of_node(chip->of_node, np) {
260 if (!of_property_read_bool(np, "gpio-hog"))
263 desc = of_parse_own_gpio(np, chip, &name, &lflags, &dflags);
267 ret = gpiod_hog(desc, name, lflags, dflags);
276 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
277 * @gc: pointer to the gpio_chip structure
278 * @np: device node of the GPIO chip
279 * @gpio_spec: gpio specifier as found in the device tree
280 * @flags: a flags pointer to fill in
282 * This is simple translation function, suitable for the most 1:1 mapped
283 * gpio chips. This function performs only one sanity check: whether gpio
284 * is less than ngpios (that is specified in the gpio_chip).
286 int of_gpio_simple_xlate(struct gpio_chip *gc,
287 const struct of_phandle_args *gpiospec, u32 *flags)
290 * We're discouraging gpio_cells < 2, since that way you'll have to
291 * write your own xlate function (that will have to retrieve the GPIO
292 * number and the flags from a single gpio cell -- this is possible,
293 * but not recommended).
295 if (gc->of_gpio_n_cells < 2) {
300 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
303 if (gpiospec->args[0] >= gc->ngpio)
307 *flags = gpiospec->args[1];
309 return gpiospec->args[0];
311 EXPORT_SYMBOL(of_gpio_simple_xlate);
314 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
315 * @np: device node of the GPIO chip
316 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
317 * @data: driver data to store in the struct gpio_chip
319 * To use this function you should allocate and fill mm_gc with:
321 * 1) In the gpio_chip structure:
322 * - all the callbacks
324 * - of_xlate callback (optional)
326 * 3) In the of_mm_gpio_chip structure:
327 * - save_regs callback (optional)
329 * If succeeded, this function will map bank's memory and will
330 * do all necessary work for you. Then you'll able to use .regs
331 * to manage GPIOs from the callbacks.
333 int of_mm_gpiochip_add_data(struct device_node *np,
334 struct of_mm_gpio_chip *mm_gc,
338 struct gpio_chip *gc = &mm_gc->gc;
340 gc->label = kstrdup(np->full_name, GFP_KERNEL);
344 mm_gc->regs = of_iomap(np, 0);
350 if (mm_gc->save_regs)
351 mm_gc->save_regs(mm_gc);
353 mm_gc->gc.of_node = np;
355 ret = gpiochip_add_data(gc, data);
361 iounmap(mm_gc->regs);
365 pr_err("%s: GPIO chip registration failed with status %d\n",
369 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
372 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
373 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
375 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
377 struct gpio_chip *gc = &mm_gc->gc;
383 iounmap(mm_gc->regs);
386 EXPORT_SYMBOL(of_mm_gpiochip_remove);
388 #ifdef CONFIG_PINCTRL
389 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
391 struct device_node *np = chip->of_node;
392 struct of_phandle_args pinspec;
393 struct pinctrl_dev *pctldev;
396 static const char group_names_propname[] = "gpio-ranges-group-names";
397 struct property *group_names;
402 group_names = of_find_property(np, group_names_propname, NULL);
405 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
410 pctldev = of_pinctrl_get(pinspec.np);
411 of_node_put(pinspec.np);
413 return -EPROBE_DEFER;
415 if (pinspec.args[2]) {
417 of_property_read_string_index(np,
418 group_names_propname,
421 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
426 /* npins != 0: linear range */
427 ret = gpiochip_add_pin_range(chip,
428 pinctrl_dev_get_devname(pctldev),
435 /* npins == 0: special range */
436 if (pinspec.args[1]) {
437 pr_err("%s: Illegal gpio-range format.\n",
443 pr_err("%s: GPIO group range requested but no %s property.\n",
444 np->full_name, group_names_propname);
448 ret = of_property_read_string_index(np,
449 group_names_propname,
455 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
460 ret = gpiochip_add_pingroup_range(chip, pctldev,
461 pinspec.args[0], name);
471 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
474 int of_gpiochip_add(struct gpio_chip *chip)
478 if ((!chip->of_node) && (chip->parent))
479 chip->of_node = chip->parent->of_node;
484 if (!chip->of_xlate) {
485 chip->of_gpio_n_cells = 2;
486 chip->of_xlate = of_gpio_simple_xlate;
489 if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
492 status = of_gpiochip_add_pin_range(chip);
496 /* If the chip defines names itself, these take precedence */
498 of_gpiochip_set_names(chip);
500 of_node_get(chip->of_node);
502 return of_gpiochip_scan_gpios(chip);
505 void of_gpiochip_remove(struct gpio_chip *chip)
507 gpiochip_remove_pin_ranges(chip);
508 of_node_put(chip->of_node);